1. Technical Field
The present invention relates to an ink composition for ultraviolet curable ink jets, an ink jet recording apparatus using the same, an ink jet recording method using the same, and an ink set.
2. Related Art
In the past, a variety of modes were used as recording methods to form images on recording media, such as paper, based on image data signals. Among them, an ink jet system uses a cheap apparatus, in which an ink is discharged only on necessary image portions so as to directly form images on a recording medium, and therefore the ink can be used efficiently, and the running cost is cheap. Furthermore, the ink jet mode makes little noise, and is thus excellent as a recording method.
In recent years, an ink composition for ultraviolet curable ink jets which is cured when ultraviolet rays are irradiated has been used as an ink composition that can provide favorable water resistance, solvent resistance, abrasion resistance, and the like in the recording method of an ink jet mode.
For example, JP-A-2008-280383 discloses an ink composition for ultraviolet curable ink jets which is composed of 2-(2-vinyloxyethoxy)ethyl acrylate, tripropylene glycol diacrylate, an acrylic resin, and a photopolymerization initiator.
In addition, JP-A-2009-226863 discloses a liquid of an adhesive precursor for ultraviolet curable ink jets which is composed of N-vinyl caprolactam, 2-ethylhexyl acrylate, isooctyl acrylate, a polymerization inhibitor, an acylphosphine oxide-based photopolymerization initiator, an iodonium salt-type polymerization initiator, 2-(2-vinyloxyethoxy)ethyl acrylate, a dispersant, and an acrylic resin.
In addition, JP-A-2009-57548 discloses a photo curable ink composition including a photopolymerization initiator produced by mixing a dendritic polymer, 2-(vinyloxyethoxy)ethyl acrylate, acylphosphine oxide, and acetophenone.
However, when the ink composition for ultraviolet curable ink jets as disclosed in JP-A-2008-280383 is cured by irradiating ultraviolet rays, there are problems in that the curing properties are degraded, and coloration is observed from the initial phase after recording.
In addition, when the liquid as disclosed in JP-A-2009-226863 is cured by irradiating ultraviolet rays, there are problems in that the curing properties are extremely degraded, and coloration is observed from the initial phase after recording.
In addition, the photo curable ink composition as disclosed in JP-A-2009-57548 has a possibility of improving the discharge stability of the ink, and also has a possibility of improvement in terms of the curing properties when the ink composition is cured by irradiating ultraviolet rays and coloration occurring in the initial phase after recording.